The article discusses the design of a submerged tunnel in Iran, specifically at Khorramshahr. The tunnel is planned to have separate lanes for cars and a service tunnel in the middle, made up of six 80m long units. The research looked into the structural analysis of the tunnel, how it floats, hydraulic models, and the ground conditions. A new method using railways on a concrete bed slab is suggested for construction, with details on the size of segments to be carried.